3. university dean of students wishes to estimate the average number of hours students spend doing homework per week. The standard deviation from a previous study is 4 hours. How large a sample must be selected if he wants to be 96% confident of finding whether the true mean differs from the sample mean by 2 hours

Answers

Answer 1

Answer:

A sample of 17 must be selected.

Step-by-step explanation:

We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:

[tex]\alpha = \frac{1 - 0.96}{2} = 0.02[/tex]

Now, we have to find z in the Z-table as such z has a p-value of [tex]1 - \alpha[/tex].

That is z with a pvalue of [tex]1 - 0.02 = 0.98[/tex], so Z = 2.054.

Now, find the margin of error M as such

[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]

In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.

The standard deviation from a previous study is 4 hours.

This means that [tex]\sigma = 4[/tex]

How large a sample must be selected if he wants to be 96% confident of finding whether the true mean differs from the sample mean by 2 hours?

A sample of n is required.

n is found for M = 2. So

[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]

[tex]2 = 2.054\frac{4}{\sqrt{n}}[/tex]

[tex]2\sqrt{n} = 2.054*4[/tex]

Simplifying both sides by 2:

[tex]\sqrt{n} = 2.054*2[/tex]

[tex](\sqrt{n})^2 = (2.054*2)^2[/tex]

[tex]n = 16.88[/tex]

Rounding up:

A sample of 17 must be selected.


Related Questions

The running trail in the local park is 2.826 miles long. If the park board were planning to extend the trail by 1.46 miles, what would the new length of the running trail be?

Answers

Answer:

4.286

Step-by-step explanation:

you really need help with this ? you cannot just use your calculator ? that would have been faster than putting that question in here ...

remember, similar to the number positions in front of the decimal point, it is equally important to add the same positions after the decimal point.

we have 10th, 100th, 1000th, 10000th, 100000th, ... no end possible.

so we have

2.826 miles

and need to add 1.46 miles

2.826

1.46

----------

4.286

and the line of thinking goes from right to left

nothing plus 6 is 6

6 plus 2 is 8

4 plus 8 is 12, so we write 2 and carry over the 1

1 plus 2 plus 1 carry over is 4

if it helps, you can always add zeroes at the end of any digits after the decimal point, as you can also add zeroes in front to the digits before the decimal point to make both numbers have the same length and their decimal points are perfectly aligned.

our addition could have also looked like

2.826

1.460

with the same result

overall, if this is truly helping you, an example of using both leading and tailing zeroes could be

4278.9472081

0021.6380000

---------------------

4300.5852081

Work out the area of the shape,show working out
help me and I think I did the sides wrong

Answers

25 x 10 = 250
11 x 6 = 66
250 - 66 = 184 cm

Congruent sides???????????

Answers

Answer:

the second option : ST and WX

Step-by-step explanation:

congruent means they would completely cover each other when oriented in the same direction and positioned at the same location.

after dying the two mirroring actions we get

VS correlates to ZW

ST correlates to WX

TU correlates to XY

UV correlates to ZY


11 Emilio makes metal fences.
He is making a fence using this design.
1.44 m
DO NOT WRITE IN THIS AREA
1.8 m
.
The fence will need
3 horizontal metal pieces of length 1.8m
2 tall metal pieces of length 1.44 m
5 medium metal pieces
6 short metal pieces as shown on the diagram.
The heights of the tall, medium and short metal pieces are in the ratio 9:8:7
.
How many metres of metal in total does Emilio need to make the fence?

Answers

Answer:

Step-by-step explanation:   7  3  13  31

3 × 1.8      long pieces                                  Calculate the ratios

2 × 1.44    9  tall vertical piece                     1.44 / 9  = x / 9      x = 1.44

5 × ___    8  medium vertical pieces          1.44 / 9  = x / 8      x = 1.28

6 × ___    7  short vertical pieces                1.44 / 9  = x / 7       x = 1.12

3 × 1.8      long pieces

2 × 1.44    9  tall vertical piece                     1.44 / 9  = x / 9      x = 1.44

5 × 1.28    8  medium vertical pieces          1.44 / 9  = x / 8      x = 1.28

6 × 1.12    7  short vertical pieces                1.44 / 9  = x / 7       x = 1.12

3 × 1.8      long pieces                                 =  5.4 m

2 × 1.44    9  tall vertical piece                   =  2.88  m

5 × 1.28    8  medium vertical pieces        =  6.4 m

6 × 1.12    7  short vertical pieces              =   6.72 m                  

                                                Total           =  21.4  m

Why is the number of operators per shift multiplied by approximately 4.5 to obtain the total number of operators required to run the plant

Answers

I believe you meant "why is the number of shifts multiplied by approximately 4.5 to obtain the total number of operators required to run the plant"

Answer and Explanation:

There are 3 shifts per day, 49 weeks per year and 5 shifts per operator per week

To get total number of operators required to run the plant, we multiply number of shifts in a year by number if operators per shift.

49 weeks×5 shifts= 245 shifts per operator per year

365×3 shifts= 1095 shifts per year

1095/245=4.5 operators per shift

total number of operators required to run the plant(per day) = 4.5×3= 13.5 approximately 14

total number of operators required to run the plant(per year) =4.5×1095=4927.5 approximately 4928

the sum of the square of the number and a second number is 42

Answers

Step-by-step explanation:

x+x squared =42. The square of the number is the number square. By my incredibly accurate guess and check strategy (works most of the time )6*6 = 36+6=42

A family eats out at a restaurant and the total for their meals is $73.89. They also pay sales tax of 5.8% and leave a tip for their server. If the family leaves a total of $93, which of the following might be a description of the service they received?
a.
They left a 10% tip, so the service was probably below average.
b.
They left a 15% tip, so the service was probably average.
c.
They left a 20% tip, so the service was probably above average.
d.
They left a 25% tip, so the service was probably outstanding.

Answers

C. 20%

$73.89 • 5.8% = 4.29
73.89 + 4.29 = 78.18
78.18 • 20% = 15.636 so 15.64
78.18 + 15.64 = 93.82
Hope it helps

The answer is They left a 20% tip, so the service was probably above average.

What is percentage?

A percentage is a number or ratio that can be expressed as a fraction of 100. A percentage is a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign, "%", although the abbreviations "pct.", "pct" and sometimes "pc" are also used. A percentage is a dimensionless number; it has no unit of measurement.

here, we have,

First step is to the amount of the sales tax.

If 100% is $73.89,

5.8% will be x (tax):

100% : $73.89 = 5.8% : x.

x = $73.89 * 5.8% : 100%.

x = $4.28.

Now, we have the price for meals, sales tax, and the total amount of money left, so we can calculate how much the tip is:

$93.00 - $73.89 - $4.28 = $14.83.

So, the tip is $14.83.

Let represent it as percent.

If $73.89 is 100%, $14.83 will be x.

$73.89 : 100% = $14.83 : x.

x = $14.83 * 100% : $73.89.

x = 20%.

So, they left a 20% tip, so the service was probably above average.

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If a+bi, where b is not equal to 0, is a complex zero of a polynomial with real coefficients, then so is its _____ , a-bi.

a.) linear factorization
b.) irreducible factor
c.) reducible factor
d.) complex factor
e.) fundamental theorem
f.) conjugate​

Answers

Hello,

answer f: conjugate

if all coefficients are real and a+ib a zero, its conjgate a-ib is also a zero.

Please help me out with these questions :

Answers

Answer:

Step-by-step explanation:

1. 3/7 x = 12

  3x = 84

    x = 28

2. 3x+ 6 = 39

   3x = 33

    x = 11

3. 1/3 x - 3/4 x = 15

    9x  - 4x  = 180

       x =  36

4.   1/4 x = x -21

      3/4 x = 21

      3x = 84

        x=28

5.    86-36 = 50

      50/2

       25

Please help! Rewrite the function

Answers

Answer:

The answer is below

Step-by-step explanation:

A function is used to show the relationship between two or more variables. This variables are known as the input variables and output variables.

The input variables are variables which do not depend on other variables while the output variables are variables that depends on other variables.

Given that g(x) = 12x / (x-5); rewriting in the form g(x) = [a/(x-h)] + k, gives:

[tex]g(x)=\frac{60}{x-5}+12[/tex]

The graph of g(x) was plotted using online geogebra graphing calculator. The graph is attached.

Find the probability of selecting 3 cards from a standard deck without
replacing them and all 3 are hearts.

Answers

Answer:

B

Step-by-step explanation:

THere are 52/4= 13 hearts we can draw

The number of ways to draw 3 hearts from 13 is

13C3= 286

The number of ways to draw 3 cards from 52 is

52C3= 22100

divide these

286/22100= 11/850

This is answer B

An RLC series circuit has an applied voltage of 240 volts. R = 48 ohm, XL = 100 ohm, and XC = 36 ohm. What is the circuit impedance (Z)?

Answers

9514 1404 393

Answer:

  48 +j64 ohms

Step-by-step explanation:

The impedance of a series circuit is the sum ...

  R + jXl -jXc

  = 48 +j100 -j36

  = 48 +j64 . . . . ohms

_____

Additional comment

"j" is the electrical engineer's name for √-1, because "i" is used to represent current.

Long division: 2/ 2769

Answers

Answer:

1384.5

Step-by-step explanation

Diviseion is just the oppisite of multiplication so you can think to yourself that what times two equals 2769. If you multiply 1384.5 on a calculater you get 2769.

1384.7 I think I’m not sure tho

Zach read a book for 10 minutes every weekend in the first month, 20 minutes in the second month, 40 minutes in the third month, and 80 minutes in the fourth month.
Victoria read a book for 35 minutes every weekend in the first month, 50 minutes in the second month, 65 minutes in the third month, and 80 minutes in the fourth month.

Which statement best describes the methods used by Zach and Victoria to increase the time they spent reading a book? (1 point)

Select one:
a. Zach's method is linear because the number of minutes increased by an equal factor every month.
b. Victoria's method is linear because the number of minutes increased by an equal number every month.
c. Both Victoria's and Zach's methods are exponential because the number of minutes increased by an equal factor every month.
d. Both Victoria's and Zach's methods are exponential because the number of minutes increased by an equal number every month.

Answers

9514 1404 393

Answer:

  b. Victoria's method is linear because the number of minutes increased by an equal number every month

Step-by-step explanation:

Zach's reading doubled each month, a characteristic of an exponential function.

Victoria's reading increased by 15 minutes each month, characteristic of a linear function.

The only reasonable description among those offered is the one shown above: choice B.

Let F(x) = x^2 – 15 and
G(x)= 4 - x
Find (F/G)(–7) =

Answers

Answer:

[tex]\displaystyle \bigg( \frac{F}{G} \bigg)(-7) = \frac{34}{11}[/tex]

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right

Algebra I

FunctionsFunction Notation

Step-by-step explanation:

Step 1: Define

Identify

F(x) = x² - 15

G(x) = 4 - x

Step 2: Find

Substitute in functions:                                                                                     [tex]\displaystyle \bigg( \frac{F}{G} \bigg)(x) = \frac{x^2 - 15}{4 - x}[/tex]

Step 3: Evaluate

Substitute in x [Function (F/G)(x)]:                                                                    [tex]\displaystyle \bigg( \frac{F}{G} \bigg)(-7) = \frac{(-7)^2 - 15}{4 - (-7)}[/tex]Exponents:                                                                                                         [tex]\displaystyle \bigg( \frac{F}{G} \bigg)(-7) = \frac{49 - 15}{4 - (-7)}[/tex]Subtract:                                                                                                            [tex]\displaystyle \bigg( \frac{F}{G} \bigg)(-7) = \frac{34}{11}[/tex]

You return from a trip with 480 Canadian dollars. How much are your Canadian dollars worth in U.S. dollars? Use the exchange rate shown below. Currency U.S. dollars per Canadian dollar Canadian dollars per U.S. dollar Canadian dollar 0.5823 1.717 The 480 Canadian dollars are equivalent to about $ (Round to the nearest cent as needed.)​

Answers

591 Dollars 42 Cents (591 Dollars when rounded)

Find the domain and range of the function graphed below, in interval notation.

Answers

Answer:

Domain: [-2,1)

Range: [0,4]

Step-by-step explanation:

The required domain and range of the function graphed are -2 ≤ x < 1 and 0 ≤ y ≤ 4.

Given that,
To determine the domain and range of the function graphed below, in interval notation.

What is the range?

Range, it is the set of the values that come out to an outcome for a certain mathematical operations.

Here,
The projected line of the curve on the horizontal axis is from greater and equal to -2 to less than 1,
Domain = -2 ≤ x < 1
The projected line of the curve on  the vertical axis is from greater or equal to 0 to less than or equal to 4,
Range = 0 ≤ y ≤ 4.

Thus, the required domain and range of the function graphed are -2 ≤ x < 1 and 0 ≤ y ≤ 4.

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Which of the following statements must be true about this diagram? Check all
that apply.
4 3
1
1
N
A. The degree measure of 23 equals the sum of the degree
measures of 21 and 22.
B. m23 is greater than m 2
C. The degree measure of 24 equals the sum of the degree
measures of 22 and 23.
D. m 4 is greater than m_2.
E. m24 is greater than m 1.
F. The degree measure of 24 equals the sum of the degree measures
of 21 and 22.

Answers

Answer:

D, E, and F

Step-by-step explanation:

✔️Statement D is true:

Rationale: m<4 is more than 90°, while m<2 is less than 90°. Therefore m<4 is greater than m<2

✔️Statement E is true:

Rationale: m<4 is more than 90°, while m<1 is less than 90°. Therefore m<4 is greater than m<1

✔️Statement F is true:

Rationale:

m<4 is an external angle of the triangle.

m<1 and m<2 are interior angles that are opposite to m<4. Therefore, based on the external angle theorem of a triangle,

m<4 = m<1 + m<2

A triangle has vertices at L(2, 2), M(4,4), and N(1,6).
The triangle is transformed according to the rule Ro.
Which statements are true regarding the
transformation? Select three options.
180
The rule for the transformation is (x, y) (-X, -y).
The coordinates of L'are (-2,-2).
The coordinates of Mare (-4,4).
The coordinates of N' are (6,-1).
The coordinates of N'are (-1,-6).

Answers

Answer:

The rule for the transformation is (x, y) (-x, -y).

The coordinates of L'are (-2,-2).

The coordinates of N'are (-1,-6).

Step-by-step explanation:

Given

[tex]L = (2,2)[/tex]

[tex]M = (4,4)[/tex]

[tex]N = (1,6)[/tex]

[tex]Ro=180[/tex]

Required

Select three options

The rule to this is:

[tex](x,y) \to (-x,-y)[/tex]

So, we have:

[tex]L = (2,2)[/tex]

[tex]L' =(-2,-2)[/tex]

[tex]M = (4,4)[/tex]

[tex]M =(-4,-4)[/tex]

[tex]N = (1,6)[/tex]

[tex]N' = (-1,-6)[/tex]

I WILL MARK THE ANSWER AS BRAINLIEST IF RIGHT

PLEASE HELP ME BE CORRECT BEFORE ANSWERING PLEASE

Answers

9514 1404 393

Answer:

  D  neither

Step-by-step explanation:

Reflection across a vertical line is required to change the figure left-to-right without changing it top-to-bottom. Translation along a directed line segment must then map corresponding points.

Sequence A involves reflection over a horizontal line, so can be rejected immediately. Sequence B does the translation so that point N gets moved to the location of point B. However, point N corresponds to point D (see the similarity statement), so that translation is inappropriate.

Neither sequence will map KLMN to ABCD.

Multiply the polynomial 4x(2x+3) (show work pls)

Answers

Answer:

8^2+12x

Step-by-step explanation:

4x(2x+3)

=4x times 2x+4x times 3

=4 times 2xx+4 times 3x

Answer:

8x^2 +12x

Step-by-step explanation:

Step 1) Multiply each term in the parentheses by 4x

4xx2x+4xx3

Step 2) Calcuate the product

8x^2 +12x

Sofia bought a clothes iron that was discounted 15% off of the original price of $35. What was the sale price of the clothes iron?

Answers

Answer:

35 - 0.15 * 35 so it is $29.75

Step-by-step explanation:

I got u

Answer:

$29.75

Step-by-step explanation:

15% = .15

.15 x 35 = 5.25

35 - 5.25 = 29.75

What is the range of g?
y
--
.
9
7.
6+
5+
4+
3+
2+
1+
.
3
{4}}
-7 -6 -5 -4 -3 -2
+++
2 3 4 5 6 7
-2
-3
-4+
-5
-6+
7
7

Answers

Answer:

y 9 5 473648

Step-by-step explanation:

Get brainly if right!! Plsss help

The 8t h term in the arithmetic sequence is 17, and 12t h term is 25. Find the first
term, and the sum of the first 20 terms.

Answers

Step-by-step explanation:

t8 = a1 + (n - 1)*d

t8 = 17

17 = a1 + 7*d

t12 = 25

25 = a1 + 11d

17 = a1 + 7d Subtract

8 = 4d Divide by 4

8/4 = 4d/4

2 = d

17 = a1 + 7d

17 = a1 + 7*2

17 = a1 + 14 Subtract 14

3 = a1

Sum 20 terms

The 20 term = a1 + 19*2

The 20 term = 3 + 38

= 41

Sum = (a1 + a20) * 20 / 2

Sum = (3 + 41)* 20/2

Sum = 44 * 10

Sum = 440

Use Cramer's Rule to solve (if possible) the system of linear equations.

x1 + 2x2 =8
- x1 + x2 = 1

Required:
Find the coefficient matrix.

Answers

Answer:

x1 = 2

x2 = 3

Step-by-step explanation:

[tex]x_1=\frac{D_{x1}}{D}\\\\x_2=\frac{D_{x2}}{D}[/tex]

Here D is the coefficient matrix.

Hence

[tex]x_1=\frac{6}{3}\\x_1=2[/tex]

&

[tex]x_2=\frac{9}{3}\\x_2=3[/tex]

The following is a scatterplot of the percent of children under age 18 who are not in school or in the labor force vs. the number of juvenile violent crime arrests for each of the 50 states. The least-squares regression line has been drawn in on the plot. We would like to predict what the number of juvenile violent crime arrests would be in a state if 25% of children are not in school or in the labor force. This is called

Answers

Answer:

Extrapolation

Step-by-step explanation:

From the linear regression plot created in the picture given, se could see that Tha percentage of student covered by the the plot is just above 16%. Therefore, to predict the percentage of the number of juvenile violent crime arrests would be in a state if 25% of children are not in school or in the labor force will require us to assume that the current trend continues into the future. Hence, we use the information and indications we have at present to make prediction into the future based on the assumption that we the current trend will remain relevant and applicable. This assumption into the future based on current trend is called EXTRAPOLATION.

Jessica purchases a kayak in Florida, where the state sales taxes are 6%. She paid $72 in sales tax. What was the retail price of the kayak?

Answers

Answer:

72 is 6% of 1200.

Step-by-step explanation:

Multiply 72 by 100.

72*100

Then divide the number by 6

(72*100)/6

You should get 1200.

the Barnes family drove 140 miles the first day and 220 miles on the second day. If they drove about 60 miles per hour, approximately how many hours did they drive? ​

Answers

140+220=360
60x6=360
therefore your answer is 6 hours

A study is done to determine the average salary for all Santa Clara County teachers. If we were to randomly pick 15 schools in Santa Clara County and average together the salaries of all teachers, would this be a good sampling technique or a bad sampling technique

Answers

Answer:

Good sampling technique

Step-by-step explanation:

In other to determine the mean value for a population, it may be necessary to make inference from the a small subset of the population, called the sample, if it is impossible, difficult or inefficient to get all population data. Hence, in other to select a subset of the population, then the sample must be selected at random, such that all elements of the population have equal chances of being selected and hence, be representative of the population. Since, the sampling technique adopted above is done at random, hence, it is a good sampling technique.

Consider a relation on the set of all states in the United States given by: two states are related if they have a border in common. Is it an equivalence relation

Answers

Answer:

Yes it is an equivalence relation

Explanation:

An equivalence relation is a binary relation between two values that are symmetric, transitive and reflexive. In other words, when we say a value x is equal(using "=") to a value y, there is an equivalence relation between them.

Example, given set {x, y, z} where ~ means equivalence:

x ~ y if y ~ z means symmetric

since x ~ y and y ~ z, then x ~ z means transitive

x ~ x means reflexive

Equivalence relations share a common attribute or attributes(example, a satisfying condition)

The above condition that two states are related from the set of all US states if they have a border in common satisfies the condition of equivalence listed hence it is an equivalence relation.

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